A new update from Lucy Bradshaw on SimCity offers "straight answers" from the General Manager of EA's Maxis label on the topic of "Always-Connected and why SimCity is not an offline experience." She goes into detail on all the benefits their approach to requiring the game be played online, saying: "In many ways, we built an MMO." She concludes by explaining that they recognize that there are fans who want to be able to build a single city in isolation, but this does not fit with their vision:

So, could we have built a subset offline mode? Yes. But we rejected that idea because it didn’t fit with our vision. We did not focus on the “single city in isolation” that we have delivered in past SimCities. We recognize that there are fans – people who love the original SimCity – who want that. But we’re also hearing from thousands of people who are playing across regions, trading, communicating and loving the Always-Connected functionality. The SimCity we delivered captures the magic of its heritage but catches up with ever-improving technology.

But we’re also hearing from thousands of people who are playing across regions, trading, communicating and loving the Always-Connected functionality So, could we have built a subset offline mode? Yes. But we rejected that idea because it didn’t fit with our vision

... It's always a good idea to reject what your consumers want, that's a smart business plan. Let's change around a franchise for no reason other than corporate strategy, well done.

But we’re also hearing from thousands of people who are playing across regions, trading, communicating and loving the Always-Connected functionality So, could we have built a subset offline mode? Yes. But we rejected that idea because it didn’t fit with our vision

The fans having @ea.com email addresses is just a coincidence. It's always a good idea to reject what your consumers want, that's a smart business plan. Let's change around a franchise for no reason other than corporate strategy, well done. People will enjoy that multiplayer regional shit for about as long as it takes them to realize how bereft of content and buggy the rest of the game is.